JP2020500724A - Arrangements and processes for treating surfaces - Google Patents

Abstract

An arrangement (1) for treating a surface with a jet comprising a plurality of particles, at least one nozzle designed to provide at least a stream of propellant gas mixed with the plurality of particles. An enclosure (3) of the unit (2) and the nozzle unit (2), wherein a gap (4) is formed between the nozzle unit (2) and the enclosure (3) from the nozzle unit (2). (1) including an enclosure (3) arranged at an appropriate distance. With the proposed arrangement and the proposed process for treating the surface, a particularly energy-efficient treatment of the surface can be achieved, in particular by means of thermal insulation and suppression of the formation of condensation water. This applies in particular to cleaning and removal of casting burrs or burrs. The arrangement and process can be used in particular in the production of wire or plastic products. [Selection diagram] Fig. 1

Description

  The invention relates in particular to arrangements and processes for treating surfaces with jets comprising a plurality of particles.

  Often, surfaces require mechanical cleaning. For example, in the production of wires, it may be necessary to clean the finished product, for example to guarantee product quality. Known solutions for doing this use various chemical and / or mechanical cleaning processes. For example, the following are considered: polishing, brushing, ultrasonic exposure or superheated steaming. In particular, it is also known to treat the surface with a jet of carbon dioxide particles.

  These processes are also used in the production of plastic products to remove casting burrs from the surface of the produced plastic product.

  For example, in known processes in which solid particles of carbon dioxide are used, the outer wall of the nozzle often becomes cold enough to allow condensed water to form and freeze there, especially at low temperatures. This can be detrimental to the use of such a nozzle. Also, energy efficiency may be reduced.

  Based on this, it is an object of the present invention to at least partially overcome the technical problems described in connection with the prior art. In particular, it is intended to present an energy efficient arrangement for treating a surface. The corresponding process is also intended to be presented.

  These objects are achieved by an arrangement and a process for treating a surface according to the features of the independent claims. Further advantageous refinements of the arrangement and the process are provided in the respective independent claims. Features described separately in the claims may be combined with one another in any desired technically meaningful way, and may be supplemented by explanatory material from the description, which may A further modification will be described.

According to the present invention, an arrangement for treating a surface with a jet comprising a plurality of particles is presented. The configuration is at least
-At least one nozzle unit designed to provide a stream of propellant gas mixed with the plurality of particles;
An enclosure of the nozzle unit, the enclosure being located at a distance from the nozzle unit such that a gap is formed between the nozzle unit and the enclosure.

  The described arrangement can be used, for example, not only in the production of wires and plastic products in particular, but also in other applications, especially in the case of carbon dioxide jets, in principle. With the described arrangement, for example, cleaning of the surface of a produced wire or a produced plastic product can be performed. Cast burrs or burrs may also be removed from the surface of the produced wire or plastic product. Removal of cast burrs or burrs means that excess material is removed from the surface. Excess material can be formed as casting burrs or burrs, particularly where the parts of the mold are placed together and / or where entry of the casting material into the mold is provided.

  The particles are preferably formed from a material that is liquid or gaseous at room temperature. The treatment of the surface can be carried out without leaving residues of the substance on the surface, especially when the substance is gaseous at room temperature. The substance is preferably carbon dioxide. The particles may take the form, in particular, of a snowy shape, such as solid carbonic acid.

  The components of the arrangement, especially those that may come into contact with the substances and / or particles, are preferably formed using a material that can withstand the low temperatures expected when it occurs. For solid carbon dioxide, the temperature is, for example, about -80C. Steel, particularly preferably high grade steel, is preferred as the material for the configuration. Conversely, preferably, the enclosure that cannot contact the substance and / or particles may be formed from another material. In particular, the enclosure is preferably formed of a material having a lower thermal conductivity than steel.

  To generate a jet comprising a plurality of particles, a stream of propellant gas is first provided to a nozzle unit. This can be performed, for example, by a compressor. The stream of propellant gas is preferably a stream of compressed air. However, gases other than air, such as nitrogen or carbon dioxide, may also be used.

  The stream of propellant gas may, for example, be mixed with particles, where the particles are formed from a solid starting material and introduced into the stream of propellant gas, or a liquid starting material is injected into the nozzle unit, As a result, snow-like forms can arise, in particular, from liquid starting materials.

  The enclosure preferably surrounds the area of the nozzle unit that is cold during operation. Low temperatures are in this context to be understood as meaning normal room temperatures, in particular below 20 ° C., and especially below 0 ° C. It is also preferred that the entire outer wall of the nozzle unit is surrounded by the enclosure.

  The nozzle unit may be insulated from the surroundings by the enclosure. Insulation can be achieved, in particular, by a gas flowing through the gap, such as air or nitrogen. Therefore, it is also preferable that the nozzle unit and the enclosure are formed of a material having low thermal conductivity. This can be, for example, a plastic, especially a foamed plastic or a plastic-metal composite. Insulation may be more pronounced the lower the gas pressure in the gap between the nozzle unit and the enclosure. Therefore, it is also preferable that the gap has a negative pressure of less than 300 hPa [hectopascal] or a vacuum with a pressure of less than 300 hPa.

  Gas within the gap may equally generate the described adiabatic effect when flowing through the gap as a stream of gas. Apart from the adiabatic effect, such a gas stream can inhibit the formation of condensed water particularly well. This is because any condensed water that may form is carried away by the gas stream. Since the gas stream preferably has a low moisture content before entering the gap, the gas stream is excellent for reducing the generation of condensed water and nevertheless reabsorbing the condensed water generated. . If the dry gas stream flows over the cold surface of the nozzle unit, the low moisture content around the surface may prevent or at least reduce the formation of condensed water. The condensed water that nevertheless forms can be directly absorbed and removed by the gas stream after the formation.

  In a preferred embodiment of the arrangement, the enclosure is at least partially formed of (or from) plastic.

  Due to the thermal properties of plastics, this material is particularly preferred for enclosures. This applies in particular to the thermal conductivity and heat capacity of plastics. Plastics may allow particularly good thermal insulation around the nozzle unit.

  In a further preferred embodiment of the arrangement, the gap has the same extent at all points of the nozzle unit.

  In this embodiment, the gas stream may flow uniformly through the gap. This can prevent the formation of condensed water from being sufficiently suppressed at individual points in the gap as a result of too low a flow rate. Areas of the gap that are too small in some respects can also result in inadequate insulation around. Then, in this regard, gaps that are too wide in some respects can unnecessarily increase the size of the arrangement.

  In a further preferred embodiment of the arrangement, the inner nozzle unit comprises at least a mixing chamber and an inner nozzle.

  The mixing chamber is preferably designed to mix the stream of propellant gas with the plurality of particles. This should be understood to mean that the mixing chamber is configured such that, after passing through the mixing chamber, the stream of propellant gas contains a plurality of particles and is connected to a particle generator. In this way, a stream of the propellant gas mixed with the plurality of particles can exit the nozzle unit through the inner nozzle.

  In a further preferred embodiment of the arrangement, the inlet to the mixing chamber has an inlet cross section different from the nozzle cross section of the inner nozzle.

  Preferably, an inner nozzle is adjacent to the mixing chamber and connected thereto with respect to flow. The inner nozzle has an outlet for a stream of propellant gas, and the nozzle cross-section of the inner nozzle is first reduced in size to a minimum nozzle cross-section as it progresses from the mixing chamber and then increased in size again Is also preferred. It is also preferred that the area quotient of the minimum nozzle cross-sectional area and the inlet cross-sectional area is in the range of 15 to 300, preferably 25 to 225.

  It has been surprisingly found from experiments that the ratio of the inlet cross section to the minimum nozzle cross section, in particular the area index, has a particularly large effect on the intimate mixing of the propellant gas stream with the particles. The effect of the area index was found to be significantly greater than that of individual, habitually varying parameters, among others.

  In a further preferred embodiment, the arrangement also includes a particle generator.

  The particle generator is preferably designed to generate a plurality of particles and introduce them in a solid state into the mixing chamber. The particle generator preferably has at least one screen plate, which allows a plurality of particles to be formed in the solid state by forcing the solid starting material through the screen plate. The nozzle unit also preferably has a propellant gas line with a propellant gas nozzle for introducing propellant gas into the mixing chamber, and an outlet from the mixing chamber for a stream of propellant gas.

  The particle generator is preferably configured such that the solid starting material can be pressed into the screen plate by a conveying screw or by pneumatic or mechanical pressing. The generation of particles by the particle generator provides particularly large particles and allows them to mix with the stream of propellant gas. As such, the particles are particularly large, for example, than can be formed by atomization (expansion) of liquid carbon dioxide. Larger particles can have greater kinetic energy and thus have a greater effect on surface treatment. For example, large particles can remove surface heavy clay. The fact that the screen plate allows the generation of large particles of uniform size means that a large and uniform effect can be achieved with the described arrangement.

  According to a further aspect of the present invention, a process for treating a surface with a jet comprising a plurality of particles is presented, and an arrangement as described and used.

  Furthermore, the particular advantages and design features of the arrangement described above may also apply and be incorporated into the described process, and vice versa.

In a preferred embodiment of the process, the treatment of the surface comprises:
-Cleaning the surface, and-removing at least one of the casting burrs or burrs from the surface.

  The specified steps may be performed alternatively or cumulatively, i.e., the surface may simply be cleaned, just cast burrs or burrs removed, or both cleaning and casting burrs or burrs removal may be performed. May be.

  The invention and the technical environment are described in more detail below on the basis of figures. The figures show particularly preferred exemplary embodiments, but the invention is not limited thereto. In particular, it should be pointed out that the relative sizes of the figures and especially of the figures are only schematic.

1 schematically shows a side sectional view of an arrangement for treating a surface.

  FIG. 1 shows a side cross-sectional view of an arrangement 1 for treating a surface with a jet containing a plurality of particles. Arrangement 1 includes a nozzle unit 2 designed to provide a stream of propellant gas mixed with a plurality of particles. The nozzle unit 2 is surrounded by an enclosure 3. The enclosure 3 is arranged at a distance from the nozzle unit 2 such that a gap 4 is formed between the nozzle unit 2 and the enclosure 3.

  The nozzle unit 2 includes a mixing chamber 5 for mixing a stream of propellant gas with a plurality of particles. The nozzle unit 2 also includes an inner nozzle 6 with an outlet 7. The nozzle unit 2 also includes a particle generator 8 designed to generate a plurality of particles and introduce them in a solid state into the mixing chamber 5. The particle generator 8 has a screen plate 11 and a conveying screw 12. By pushing the solid starting material 13 through the screen plate 11 by the conveying screw 12, a plurality of particles are formed in a solid state and are introduced into the mixing chamber 5. Furthermore, the nozzle unit 2 has an injection gas line 9 provided with an injection gas nozzle 10 for introducing an injection gas into the mixing chamber 5 via an inlet 14.

  With the proposed arrangement and the proposed process for treating the surface, a particularly energy-efficient treatment of the surface can be achieved, in particular by means of thermal insulation and suppression of the formation of condensation water. This applies in particular to cleaning and removal of casting burrs or burrs. The arrangement and process can be used in particular in the production of wire or plastic products.

DESCRIPTION OF SYMBOLS 1 Arrangement configuration 2 Nozzle unit 3 Enclosure 4 Gap 5 Mixing chamber 6 Inner nozzle 7 Outlet 8 Particle generator 9 Injection gas line 10 Injection gas nozzle 11 Screen plate 12 Transport screw 13 Solid starting material 14 Inlet

Claims (9)

An arrangement (1) for treating a surface using a jet including a plurality of particles, wherein at least:
At least one nozzle unit (2) designed to provide a stream of propellant gas mixed with the plurality of particles;
An enclosure (3) of the nozzle unit (2), wherein a gap (4) is formed from the nozzle unit (2) between the nozzle unit (2) and the enclosure (3). And an enclosure (3) located at a distance.   Arrangement (1) according to claim 1, wherein the enclosure (3) is at least partially formed of plastic.   Arrangement (1) according to claim 1 or 2, wherein the gap (4) has the same range at all points of the nozzle unit (2).   Arrangement (1) according to any of the preceding claims, wherein the nozzle unit (2) comprises at least a mixing chamber (5) and an inner nozzle (6).   Arrangement (1) according to claim 4, wherein the inlet (14) into the mixing chamber (5) has an inlet cross-sectional area different from the nozzle cross-sectional area of the inner nozzle (6).   Arrangement (1) according to any of the preceding claims, which also comprises a particle generator (8).   A process for treating a surface with a jet comprising a plurality of particles, wherein the arrangement (1) according to any one of claims 1 to 6 is used.   The process according to claim 7, wherein a stream of gas is generated between the nozzle unit (2) and the enclosure (3). The treatment of the surface comprises:
9. The process of claim 8, comprising:-cleaning the surface; and-removing cast burrs or burrs from the surface.

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